WO 01/69179 describes a device for attachment to the shoe of a user, which measures footfalls and thereby calculates the distance run or walked by the wearer of the device, to determine a level of exercise by the wearer of the device. This document also describes the prescription of exercise levels according to a percentage of a subject's aerobic capacity (maximal VO2 or VO2 max), with the capacity being determined as a constant (known as Cooper's constant) multiplied by the distance a subject can run in 12 minutes.
Polar Electro of Kempele, Finland produce an exercise monitor sold as the S625X running computer, which is proposed to operate in conjunction with the Nokia 5140 mobile phone (from Nokia Corporation). As described at http://www.polar.fi/mobileconnectivity/, the running computer receives data from a foot-worn pedometer to calculate distance travelled, and receives heart rate information from a chest-worn heart monitor. Instantaneous and cumulative data are displayed on the wristwatch style running computer.
After the session is complete the running computer can connect via infrared with a Nokia 5140 phone runs a software application to calculate and display statistics for the exercise session. The phone can also connect with another phone (via SMS message) to share the data, or to a personal computer (via infrared) to insert the session statistics into a training spreadsheet from which updated training goals are calculated. This data can also be sent to a web service for similar purposes.
Both WO 01/69179 and the Nokia/Polar devices rely on foot-worn and/or chest-worn units to measure evidence of exercise activity. The alternative to such measuring devices is to conduct laboratory or clinic sessions with dedicated treadmills, electrocardiograms and lung volume measurement apparatuses to obtain data resulting directly from the exercise activity.
One shortcoming in particular of the Polar/Nokia combination is the reliance on heart rate monitoring. Targeting exercise levels at a particular cardiac rate is useful in some instances but has serious drawbacks for groups of users who do not fit the standard heart rate/exercise response profile. Such users include cardiac patients, elite athletes, post-menopausal women, diabetics, and users who are targeting a weight loss goal as opposed to a fitness goal.